Kitchen mixer impeller and mold for making

ABSTRACT

An integral impeller having equally spaced blades and a twopiece mold for making it. The impeller is cast by rotating all blades slightly with respect to the mold parting plane and a plane perpendicular to the parting plane.

United States Paieni 1191 Wallin 1451 May 22, 1973 541 KITCHEN MIXERIMPELLER AND 2,769,623 11/1956 Cawood ..416/202 MOLD FOR MAKING3,215,410 ll/l965 McMaster et al.... .259/DlG. 35 3,441,254 4/1969 Merke..416/227 [75] Inventor: Gus Waldemar Wallm, Waterbury,

Conn. FOREIGN PATENTS OR APPLICATIONS [73] Assignee: ScovillManufacturing Company, 134,701 11/1919 Great Britain ..416/202Waterbury, Conn. 919,467 2/1963 016a: Britain ..416 202 [22] Filed: June1971 Primary ExaminerEverette A. Powell, Jr. 211 App} 14 339Attorney-Dallett Hoopes 52 us. 01. ..416/77, 416/202, 416/227 [57]ABSTRACT [51] Int. Cl. ..BOli 7/24 An integral impeller having equallySpaced blades and [58] Field of Search ..416/76, 77, 227, a two piecemold for making it The impeller is cast by 28, D1629 rotating all bladesslightly with respect to the mold parting plane and a planeperpendicular to the parting [56] References Cited plane.

UNITED STATES PATENTS 4 Claims, 4 Drawing Figures 2,544,301 3/1951 Daviset al ..416/227 PATENTEBHAYZZISYS 3 734,643

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ATTORNEY KITCHEN MIXER IMPELLER AND MOLD FOR MAKING This inventionrelates to a mold for making a kitchen mixer impeller and the impelleritself. More specifically, this invention relates to a two-piece moldadapted to make an integral impeller having equispaced open blades andthe impeller itself.

In the prior art, there are a number of patents covering construction ofimpellers for kitchen mixers. Most of these constructions involve aplurality of parts which are riveted, soldered, or otherwise fastenedtogether. The hand labor involved in making such beaters has made theneed for an integrally molded impeller increasingly urgent. One answerto this need was provided in U.S. Pat. No. 3,441,254, in which animpeller and mold for making it were disclosed by Joseph P. Merke, Jr.Products as described in that patent have been objectionable, however,in that the blades were not equi-spaced. Equi-spacing of blades couldnot be achieved, according to Merke, and still have the mold halves parton the plane of two opposite blades.

The inability of impellers made according to the invention of Merke tohave equi-spaced blades has resulted in serious disadvantages. When, asis usual, two such impellers are mounted in a kitchen mixer head anddriven to counter rotate and intermesh, there has often beeninterference between the blades of the two impellers. In addition, theirregular spacing has resulted in less efficient mixing, awkwardappearance, and poor balance.

Under the present invention, a mold is provided which overcomes theobjections to the impeller of the Merke patent in that the spacing ofthe blades is uniform, eliminating interference during intermeshing inuse and providing a superior mixing and balance and an attractiveappearance.

Further features and objects of the invention will be apparent from areading of the following specification and an examination of theattached drawings wherein:

FIG. 1 shows in broken fashion an impeller made by a mold embodying theinvention;

FIG. 2 is a sectional view taken on the line 2-2 of FIG. 1;

FIG. 3 is a perspective view of one of the mold parts embodying theinvention; and

FIG. 4 is a sectional view showing the mold closed at about the line 44of FIG. 3 and showing the blades of an impeller in section.

Briefly, the invention is an impeller having equispaced blades and atwo-piece mold for making it. The impeller is cast by rotating allblades slightly with respect to the mold parting plane and a planeperpendicular to the parting plane.

Referring more specifically to the drawings, an impeller embodying theinvention is generally designated in FIG. 1. It comprises a stem 12having a stop shoulder 14 and thereabove a stub shaft 16. As isconventional, the shaft has driving ears 18 diametrically disposedthereon.

The impeller comprises four equally spaced blades 20. Each blade extendstangentially out from the lower end of the hub 21 on stem 12. As shownin FIG. 2, the first run 22 of the blades each extends out along a lineparallel to a radius of the hub. The blades then curve down into asecond, vertical run 24, the second runs being 90 apart with respect tothe axis of the impeller.

The blades then curve inward in final 26 runs parallel to the first runsand tangentially merge with a lower hub 28 with downward nib 29. Asshown in FIG. 2, the blades, in their vertical runs 24, have insidesurfaces 24a which are each perpendicular to a radius of the impeller.The outside surfaces 24b are generally also perpendicular to a radius.The blades are relatively thin, for instance, 0.08 inches in an actualmold.

A half of a mold for making the above-described impeller is shown inFIG. 3. The mold halves may be substantially identical and they areprovided with mating faces. In the stem portion of the mold, the moldfeatures a single parting plane 32 having mating grooves 34 in which thestem and stub shaft are formed. In the blade portion of the impeller,the mold half is provided with a stepped plane 36a, 36b, 36c.Cooperating grooves 38 on the two mold halves form a first pair ofdiametrically opposed blades 20' and are arranged so that the channelsforming the blades are on opposite sides of the plane A (FIG. 4) whichaligns with the plane of 36b and plane 32 and is the plane of the axisof the stem.

Each of the mold halves 30 and 30 (FIG. 4) has a deep slot 40 betweenthe grooves 38 and alongside the deep slot an upright rib 42 isprovided, receivable into the slot 40 of the other mold half. The ribsand slots together define channels 44 for forming a second pair 20" ofdiametrically opposed blades. The channels for the second pair are onopposite sides of a second plane B (FIG. 4) which is perpendicular tothe first plane A.

When the mold halves 30 and 30' are closed and plastic material isinjected into the cavities between the mold halves, an impeller isformed which, when withdrawn from its mold, provides equi-spaced blades.Preferably, the plastic material is molten zinc or other metal whichgives strength to the thin blades and may be readily finished and platedto provide a superior product.

While the invention has been shown in but one form, reasonablevariations may fall within the invention which may be defined by thefollowing claim language:

I claim:

1. An integrally cast impeller of non-ferrous metal for kitchen mixerscomprising a stem having a hub at its lower end, a plurality of bladessecured to and extending in a first run tangentially outward fromuniformly spaced points on the hub, the blades then extending downwardin longitudinal second runs of uniform thickness, and each having insideand outside faces substantially perpendicular to a radius of the axis,the second runs being apart with respect to the axis of the stem, theblades thereafter bending inward and extending in final runs parallel tothe first runs of the same blades respectively, and a lower hub, thefinal runs tangentially connected to the lower hub at points spaceduniformly thereabout.

2. An integrally cast impeller of non-ferrous metal as. claimed in claim1 wherein the metal is zinc.

3. A unitary cast impeller of non-ferrous metal for kitchen mixerscomprising a shaft defining the axis of the impeller and having a firsthub at one end, a pluraltant dimension in transverse section and eachhaving inside and outside faces substantially perpendicular to a radiusof the axis, the longitudinal runs being 90 apart with respect to theaxis, each of the blades at the 3,734,643 3 4 end of the longitudinalrun more remote from the and 90 apart with respect to the axis. upperhub extending inwardly in a final run, a lower hub disposed on the axis,the final runs extending in directions tangential to the lower hub andbeing joined to lower hub has a central depending the lower hub atpoints uniformly spaced from the axis 5 4. An impeller as described inclaim 3 wherein the

1. An integrally cast impeller of non-ferrous metal for kitchen mixerscomprising a stem having a hub at its lower end, a plurality of bladessecured to and extending in a first run tangentially outward fromuniformly spaced points on the hub, the blades then extending downwardin longitudinal second runs of uniform thickness, and each having insideand outside faces substantially perpendicular to a radius of the axis,the second runs being 90* apart with respect to the axis of the stem,the blades thereafter bending inward and extending in final runsparallel to the first runs of the same blades respectively, and a lowerhub, the final runs tangentially connected to the lower hub at pointsspaced uniformly thereabout.
 2. An integrally cast impeller ofnon-ferrous metal as claimed in claim 1 wherein the metal is zinc.
 3. Aunitary cast impeller of non-ferrous metal for kitchen mixers comprisinga shaft defining the axis of the impeller and having a first hub at oneend, a plurality of blades connected to the hub and extending away fromthe shaft and including longitudinal runs of constant dimension intransverse section and each having inside and outside facessubstantially perpendicular to a radius of the axis, the longitudinalruns being 90* apart with respect to the axis, each of the blades at theend of the longitudinal run more remote from the upper hub extendinginwardly in a final run, a lower hub disposed on the axis, the finalruns extending in directions tangential to the lower hub and beingjoined to the lower hub at points uniformly spaced from the axis and 90*apart with respect to the axis.
 4. An impeller as described in claim 3wherein the lower hub has a central depending nib.